CYP2C9*1*2 and VKORC1-1639 AA Polymorphisms Correlation with Warfarin Dose Requirement: A Case Report

CYP2C9 and VKORC1-1639 G>A genes as the genetic factors significantly influence the warfarin dose requirement in individuals. The patients with genetic variations in CYP2C9 and VKORC1 are at increased risk of adverse warfarin-related events. A young patient with atrial septal defect being highly sensitive to normal daily dose of warfarin was subjected to the study. The patient consented to genetic testing. Furthermore, DNA was isolated and PCR-RFLP performed. The patient required low warfarin dose of 11 mg/week to achieve the target international normalized ratio (INR). Genetic testing revealed that the patient carried VKORC1-1639 AA and CYP2C9*1*2 genotypes. Our findings reaffirm the significance of pharmacogenetic analysis prior to the warfarin therapy to achieve an efficient treatment and the least side/adverse drug effects.